# Valorization of Cavia porcellus By-Products via Ultrasound-Assisted Collagen Extraction: Optimization and Characterization

## TL;DR

This study uses ultrasound to extract collagen from guinea pig by-products, optimizing the process and showing the collagen's stability and potential for food and biomaterial use.

## Contribution

The novel contribution is the optimized ultrasound-assisted extraction of collagen from Cavia porcellus by-products with detailed structural and colloidal characterization.

## Key findings

- Optimal extraction conditions yielded 28.15% collagen and 4.18% hydroxyproline, matching predicted values closely.
- The extracted collagen showed a stable colloidal dispersion with a hydrodynamic diameter of 599.3 nm and −61.3 mV ζ-potential.
- FTIR and SEM confirmed the collagen's triple-helix structure and fibrillar morphology, indicating high structural integrity.

## Abstract

The by-products of Cavia porcellus (legs and head) were valorized for collagen extraction using ultrasound-assisted extraction (UAE). Process optimization was performed through response surface methodology (central composite design) considering amplitude, cycle, and time as factors. Samples were pretreated with NaOH and butyl alcohol, followed by acetic acid extraction under controlled sonication. The quadratic models for yield and hydroxyproline showed excellent fit (high R2, R2adj, and R2pred) with no significant lack of fit. The optimal conditions were identified at 100% amplitude, cycle = 1, and 27.47 min, and these were validated experimentally, yielding 28.15 ± 0.19% collagen and 4.18 ± 0.12% hydroxyproline, values that closely matched predictions. The optimal extract exhibited a hydrodynamic diameter of 599.3 nm, a ζ-potential of −61.3 mV, and a polydispersity index of 0.33, indicating a highly stable colloidal dispersion with submicron fibrils. SEM micrographs confirmed fibrillar bundles consistent with the particle size distribution, while FTIR spectra showed characteristic amide bands indicative of triple-helix preservation. These results demonstrate that UAE of guinea pig by-products produces collagen with high structural integrity and colloidal stability, highlighting its potential for food and biomaterial applications.